Motor fuel



Patented July 14, 1936 PATENT OFFICE MOTOR FUEL G.'Borden, Little Neck,N. Y., ascignor to Gasoline Antioxidant Company, Wilmington, Del., acorporation of Delaware No Drawing.

Application July 26, 1933,

Serial No. 682,269

'1 Claims.

This invention relates to the stabilization of motor fuels and moreparticularly to motor fuels of the gasoline type wherein the gasolinecontains hydrocarbons having gum-forming constituents.

The gasclines now being manufactured from petroleum and coal tar oilsoften contain unsaturated hydrocarbons which are gum-formingconstituents. The modern cracking processes which decompose oils underheat and pressure tend to form unsaturated hydrocarbons, such as theolefines, diolefines, naphthcnes and acetylenes. These unsaturatedhydrocarbons often contain and are themselves products which are easilyoxidizable and which are gum-forming constituents. The gummy materialappears to be formed by oxidation whereby a fiocculent stickyprecipitate forms in the gasoline, the formation of this precipitateoften being accelerated by sunlight. Usually when gummy materials formin the gasoline the color of the gasoline is changed. The formation ofgum tends to affect both the color ofthe gasoline and a clouding orprecipitation of a gummy product in the gasoline. The formation andremoval of gum-forming constituents tends to affect the boiling range ofthe gasoline and also the octane rating of the gasoline.

One object of the invention is to provide a method of stabilizing thegasoline whereby gumforming constituents will not precipitate.

Another object of the invention is to stabilize the color of thegasoline so that its color will remain substantially unchanged whenstanding for long periods of time.

Another object of the invention is to stabilize the octane rating of thegasoline so that its octane rating will become substantially fixed andwhereby the hydrocarbon content of the gasoline which gives it thedesired octane rating may be preserved.

Another object of the invention is to provide a method of treatinggasoline to inhibit the formation of gum in the gasoline.

Heretofore poly-hydroxy-benzenes such as pyrogallol, catechol andresorcinol have been used as gasoline stabilizers. These compounds whilegood gasoline stabilizers, catechol and pyrogallol, have objectionswhich are quite effectively overcome by the present invention. Forexample, pyrogalloland catechol. are quite soluble in water andsparingly soluble particularly in gasoline. Practically all gasoline isassociated with water in its transportation and storage and thisobjection has materially reduced the amount of pyrogallol andpyrocatechol used in stabilizing gasoline. Due to these facts it oftenhappens that if a gasoline is stabilized with pyrogallol and thenbrought into contact with water, the pyrogallol is practically allremoved from the gasoline and the stabilizing effect of pyrogallol islost. Some of the compounds which have an acid reaction such as catecholand pyrogallol have a tendency to dissolve compounds of iron fromstorage tanks and these compounds have a dark color, dark blue or black,which tends to discolor the gasoline. These colored compounds aresoluble in water and insoluble in gasoline but nevertheless theretailers of gasoline object to the presence of colored water solutionsin the gasoline.

In accordance with the present invention it has been discovered that thepoly-hydroxy-benzenes, 23 particularly the poly-hydroxy-benzenes such aspyrogallol, catechol, and phloroglucinol, may be modified by attachingto the benzene nucleus hydrocarbon radicals which make the resultingcompound substantially insoluble in water. Such 2;, compounds preservethe original grouping of thehydroxyl radicals on the benzene nucleus,thus preserving the gum-inhibiting or reducing properties of thecompounds. Furthermore it has been found that straight chainhydrocarbons may 30 be attached to the benzene nucleus as a modifyingagent and this straight chain hydrocarbon can in turn be modified byattaching thereto side chain alkyl groups or amino groups to make theresulting compound gasoline-soluble, as well as 35 beingwater-insoluble.

It further has been discovered that the hydrogen of one of the hydroxylradicals of a tri-hydroxy-benzene may be substituted by an alkyl orstraight chain hydrocarbon to form an ether 40 which is substantiallyinsoluble in water and this straight-chain hydrocarbon or alkyl groupmay be modified so as to make the compound gasolinesoluble as well aswater-insoluble. In making ethers, however, it has been found that thebest 45 results are obtained when modifying only one hydroxyl so thatthe resulting compound retains two hydroxyl groups in the molecule.

Among the compounds which have been found to be particularly effectiveas gasoline stabilizers are decyl-pymgallol, hevyl-pyogallol,alphaethyl-hexyl-pyrogallol, pyrogallol-mono heptyether,nonyl-pyrogallol and e'thyl-octyl-pynogal- 101. In general the compoundswhich have been found to be most satisfactory may be representedstructurally as follows:

4. OH ether R is an alkyl radical having Cs or higher carbon atoms whichmay or may not be modified with a side chain amino or an alkyl group.

The modified straight chain hydrocarbons which may be attached to thebenzene nucleus are straight chain hydrocarbons which have five or morecarbon atoms in the radical. It has been found that the alkyl groupshaving less than five carbon atoms do not generally form compounds whichare as insoluble in water as the straight chain hydrocarbon radicalswhich have five carbon atoms or more. Those compounds furthermore whichare gasoline-soluble preferably have the straight chain hydrocarbonradical modified by a side chain alkyl or an amino group. The ether ispreferably made by substituting a straight chain hydrocarbon for ahydrogen of a hydroxyl group and this straight chain hydrocarbon may inturn be modified in order to render the compound soluble in gasoline.

To stabilize gasoline with the compounds mentioned above it is usuallybest to dissolve a small amount of the inhibiting compound with thegasoline when it is freshly made, that is soon after the gasoline isremoved from the stills. If the gasoline is allowed to stand for anyconsiderable period after it has been made there is a polymerization orsome form of rearrangement of the compounds which increases thedifiiculty of stabilizing the gasoline. Furthermore the gasoline is soaltered that the refining process entails a loss of gasoline.

when freshly made gasoline is treated with gum-inhibiting compounds inaccordance with the present invention the amount used varies from .01 to.1% by weight of the gasoline. I have found, however, that an inhibitorused in the ratio of 8 to 15 milligramsto 100 cc. of gasoline gives thebest results. If too much inhibitor is used the tendency to developgum-forming compounds is often accelerated.

In the treatments of gasolines it has been found aomsss that crackedgasolines. particularly, contain two ,commonly-known forms of gum, apotential gum and a fixed gum. The usual tests for determining thecontent of the gasoline are the copper dish test, which consists inslowly vaporizing gasoline in a copper dish, and the pressure bomb testor accelerated storage test. The copper dish test is quite interestingand indicative of the character of the gum in some forms of gasolinebutthe accelerated bomb test is relied upon more on account of the factthat it gives an indication of gun'i formation in the gasoline duringlong storage duration.

Some examples of the use of gum inhibitors, in accordance with thepresent invention, are cited below. These tests, however, are notcomparative of the action of the diflerent inhibitors because theinhibitors have been used on different forms of gasoline, and gasolineshaving diifere'nt gum contents. Examples:

Alpha-ethybheaml pll wflllol 3%?" Potential IreSsuire gum mgs. top 11per 100 cc. bomb Pound: Gasoline blank 133 Gasollne+mm alpha-ethylhexyloi 3"i +"';i'a:aa"1

no no p Y yroml 170 2 Decvl pvroaallol Gasoline blank ll. 00 1000Gasoliilie+l0 mgs. decyl pyron 4 o Gasoline+l0 mgs. decyl pyrogal] 01washed with water... 11 v 4 Qingdao-+10 mgs. decyl pyro- 5 .o Gasodneblank I 915 41 Gsso ins-H0 mgs. decyl pyrogallol 7 0 None after G li +10d lp 3 see he ec yrogallol wash efi 30 niinutes with turbo mixer 8 0None Decyl pyrogallol-l-anthrucene Gasoline blank 249 Gasoline-H0 mgs.decyl pyroo lli a'q 'if r'ffl u aso mgs. ec pyrogalloH-I mgs.anthrioene-.. 3

Hen/l pyrogallol Gasoline blank 30 Gasoline-H0 mgs. beryl pyrogallol 6Ethyl octul pyrogallol Gasoline blank 427 1506 Gasoline of i0 mgs. ethyloctyl pyrogallol ll 22 0 In some cases where it is important to allowgasoline to stand in the light or sunlight it is quite important to havethe gasoline light-stable. Anthracene has the property of assisting ingiving a light-stable gasoline and the properties are line need not behigh provided that the inhibitor is more soluble in gasoline than inwater. It is very' desirable that all of the inhibitor be dissolved inthe gasoline, otherwise some inhibitor may stay in suspension or beprecipitated and thus affect the color and quality of the gasoline. Inorder to readily dissolve the inhibitor in the gasolinev it is desirablein many cases to dissolve the preferred inhibitor in dry alcohols orbenzoi and then put the alcohol or benzol solution into the gasoline. Ithas been found that when the poly-hydroxy compounds have been modifiedwith straight chain or modified straight chain hydrocarbons the productsformed are very soluble in most alcohols and benzol. One of the bestsolvents which has been used is a dry secondary butyl alcohol becausethis product is readily soluble in gasolines. It has also been foundthat the secondary amyl and hexyl alcohols when dry are good solventsfor the preferred inhibitors and are effective in dissolving theinhibitor in the gasoline. It has been found, furthermore. that thehigher alcohols are not as readily soluble in water as the loweralcohols and therefore the solution of these compounds in gasolineassists in preventing the inhibitor from being extracted from thegasoline when the gasoline is washed or contacted with water.

In the claims the term "gasoline" has been used in defining the motorfuel, it being understood that gasoline is a distillate which may beobtained from any form of petroleum oil or coal tar oil.

Having thus described the invention. what is claimed is:

1. A motor fuel comprising cracked gasoline normally tending to developgum on storage and a small amount of polyhydroxy benzene having an alkylradical containing from 8 to 10 carbon atoms attached to a carbon atomof the benzene nucleus, said alkylated polyhydroxy benzene being used inquantities sufficient to retard gum formation in the motor fuel.

2. A motor fuel comprising cracked gasoline normally tending to developgum on storage and 5 having incorporated therein, in an amountsufflcient to retard said gum formation, catechol having an alkylradical containing from 8 to 10 carbon atoms attached directly to thebenzene nucleus of the catechol.

3. A motor fuel comprising cracked gasoline normally tending todeteriorate and develop gums on storage and having incorporated therein,in an amount sumcient to retard said gum formation, pyrogallol having analkyl radical containing from 8 to 10 carbon atoms attached directly tothe benzene nucleus of the pyrogallol.

4. A motor fuel comprising cracked gasoline normally tending todeteriorate and develop gum onstorage and having incorporated therein adecyl pyrogallol in quantity sumcient to retard said gum formation.

5. A motor fuel comprising cracked gasoline normally tending todeteriorate and develop gum on storage and having incorporated thereinalpha-ethyl-hexyl-pyrogallol in quantity sumcient to retard said gumformation.

6. A motor fuel comprising cracked gasoline normally tending todeteriorate and develop gum on storage and having incorporated thereinethyl-octyl-pyrogallol in quantity suflicient to retard said gumformation.

7. A motor fuel comprising cracked gasoline normally tending todeteriorate and develop gum on storage and having incorporated thereinan octyl pyrogallol in quantity sufllcient to retard said gum formation.

EDMUND G. BORDEN.

